The approaches described in this section could be pursued but are not necessarily approaches that have previously been conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.
When a web client (e.g., a web browser,) attempts to access a domain, namely a website associated with the domain, a client request is transmitted to a local Domain Name System (DNS) server. The local DNS server is responsible for routing client requests to desired domains. The local DNS server, in turn, can send a request to the Global Server Load Balancer (GSLB) associated with the desired domain. The GSLB can balance client requests across multiple websites associated with the domain. In order for the GSLB to determine which website is better equipped at the moment to process a specific client request, the GSLB can instruct Site Load Balancers (SLB) associated with corresponding websites to send requests to the local DNS server. The local DNS server can respond to the SLBs, so that round trip times between the local DNS server and different SLBs can be calculated. The website with the shortest round trip between the SLB and the local DNS server can be selected for delivery of client requests for a period of time. Each website can be associated with a Virtual IP (VIP). When the GSLB decides to which website to deliver the client requests, the corresponding VIP can be returned to the GSLB. The GSLB can send the VIP of the selected web site to the local DNS server. Thereafter, the local DNS server can route client requests to the SLB associated with the selected website for a period of time.
Web sites can use a plurality of web servers to serve a number of web clients accessing the web sites. When the SLB associated with the selected website receives a client request from a web client, the SLB can select one or more web servers associated with the web site, and relay the client request to the selected web servers. The problem with existing solutions is that calculating round trips between the LDNS and sites is not necessarily indicative of the round trip between the LDNS and web servers because slow data traffic between the site and its servers can make another site a better candidate even though the roundtrip between the site and the LDNS appears to indicate otherwise. Thus, it is important to select the right site with fastest round trips between the client and the servers associated with the site.